title: Longitudinal study of smoking cessation before pregnancy and children's cognitive abilities at 56 months of age.
abstract: BACKGROUND
  An inverse relationship exists between the rates of maternal smoking during pregnancy and children's cognitive abilities. The effect of maternal cessation of smoking before pregnancy on child's cognitive development is less clear.
  
  
  OBJECTIVE
  To study whether maternal cessation of smoking before pregnancy is associated with children's cognitive abilities.
  
  
  METHODS
  The original cohort included all 1535 live-born infants admitted to the neonatal wards during 1 year and 658 randomly recruited non-admitted infants. The present study sample comprised 1019 (68.2%) children of the original sample born at term and free of any major impairment followed up to 56 months.
  
  
  METHODS
  Child's general reasoning, visual-motor integration, verbal competence, and language comprehension at 56 months of age.
  
  
  RESULTS
  The results showed that children whose mothers smoked >10 cigarettes per day before pregnancy but none during pregnancy, fared 12.07 (95% confidence interval [CI]: 4.07 to 20.08) and 11.23 (95% CI: 2.81 to 19.66) age-standardized points poorer in general reasoning and in language comprehension tests, respectively, than children of never-smokers. All results were adjusted for the sex, gestational age-adjusted birth weight, multiple/singleton pregnancy, birth order, preeclampsia, maternal diabetes, admission to neonatal ward, 5-minute Apgar score (<7), breastfeeding, parental level of education, maternal age, BMI at the end of pregnancy and single parenting.
  
  
  CONCLUSIONS
  Heavy smoking before pregnancy is associated with children's lower cognitive abilities even if the mother has quit smoking before pregnancy. Identification and intervention of heavy smoking women of fertile age would potentially improve not only their odds to become pregnant but also benefit the offspring's cognitive functioning.
authors.affiliation: Institute of Behavioral Science, University of Helsinki, Helsinki, Finland. kati.heinonen@helsinki.fi
authors.forename: Kati
authors.initials: K
authors.lastname: Heinonen
authors.forename: Katri
authors.initials: K
authors.lastname: Räikkönen
authors.forename: Anu-Katriina
authors.initials: AK
authors.lastname: Pesonen
authors.forename: Sture
authors.initials: S
authors.lastname: Andersson
authors.forename: Eero
authors.initials: E
authors.lastname: Kajantie
authors.forename: Johan G
authors.initials: JG
authors.lastname: Eriksson
authors.forename: Dieter
authors.initials: D
authors.lastname: Wolke
authors.forename: Aulikki
authors.initials: A
authors.lastname: Lano
mesh_terms: D002675:Child, Preschool; D003071:Cognition / Q000502:physiology*; D005220:Fathers; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D009035:Mothers; D011247:Pregnancy; D016540:Smoking Cessation; D012959:Socioeconomic Factors